When building with LLVM=1 for architectures like powerpc where
CONFIG_DMA_SHARED_BUFFER is not enabled, the build fails with:
ld.lld: error: undefined symbol: dma_resv_reset_max_fences
>>> referenced by helpers.c
>>> rust/helpers/helpers.o:(rust_helper_dma_resv_unlock)
The issue occurs because:
1. CONFIG_DEBUG_MUTEXES=y is enabled
2. CONFIG_DMA_SHARED_BUFFER is not enabled
3. dma_resv_reset_max_fences() is declared in the header when
CONFIG_DEBUG_MUTEXES is set
4. But the function is only compiled in drivers/dma-buf/dma-resv.c,
which is only built when CONFIG_DMA_SHARED_BUFFER is enabled
5. Rust helpers call dma_resv_unlock() which calls
dma_resv_reset_max_fences(), causing an undefined symbol
Fix this by compiling `dma-resv.c` file only when CONFIG_DMA_SHARED_BUFFER
is enabled.
Fixes: 9b836641d3 ("rust: helpers: Add bindings/wrappers for dma_resv_lock")
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260708082454.1254320-3-mkchauras@gmail.com
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